The instant invention relates to a travelling mechanism of an automatic service carriage for spinning or twisting machines whereby said automatic service carriage travels on a rail system to work stations and must travel over a curved track at the front of the machine so as to move from one side of the machine to the other.
The automatic service carriage is a self-contained assembly which must be positioned for technical reasons in one plane of movement at different locations of the textile machine. For this purpose the automatic service carriage is mounted on a running rail system. The running rail system, which consists of an outer and inner running rail is attached to the machine frame by means of supports. The automatic service carriage includes guide rollers attached to an extension bracket upon the inner running rail while the running and guide rollers of the automatic service carriage are guided on the outer running rail.
The configuration of the outer running rail system with moving gear determines the travelling attitude.
The moving gear of the automatic service carriage must therefore ensure precise guidance in relation to the work stations of the textile machine and also in travelling over curves on the outer curved track. Due to the relatively high speed as well as great weight and volume of the automatic service carriage, an unsteady transport movement is produced in curve travel.
In a known device a running wheel is rigidly installed on each of the two ends of the travelling gear of the automatic service carriage, whereby the fork of the running wheel is rotatably mounted by means of a spherical gudgeon. The formation of a wheel flange on each side of the running wheels is necessary in order to ensure true gauge in transport. Curve travel on the rail produces a high degree of sliding friction due to the different circumferential speeds of the two wheel flanges of a wheel, leading to spontaneously unsteady running and wear.
Another known development consists in equipping this running wheel with wheel flanges on both sides rotatably and independently of each other, facing the running wheel. However this solution avoids neither wear at the friction points nor spontaneous braking action.
Another device according to DE-OS 38 33 739 omits wheel flange elements on the running wheel. Three guide rollers with axles that are parallel to the guide axles of the running wheel are provided on the sides of the track in addition to the running wheel and are connected to the latter. It is a particularity of this arrangement that at least two guide rollers run in different radial planes on one edge of the curved track and that the curved track has two different radii. However, since at least two running wheels are still rigidly coupled together over a defined distance, sliding friction on the running wheels remains and sufficiently steady travel of the automatic service carriage is still not ensured.